In a Positive-Feedback System in Which Hormone a Alters the Amount

Question

In a positive-feedback system in which hormone A alters the amount of protein X
A)an increase in A always produces an increase in X.
B)an increase in X always produces a decrease in A.
C)a decrease in A always produces an increase in X.
D)a decrease in X always causes a decrease in A.
E)it is impossible to predict how A and X affect each other.

Accepted Answer

In a positive-feedback system, an increase in hormone A will stimulate an increase in the amount of protein X, which in turn will stimulate an increase in hormone A, resulting in a cycle of increasing levels. Therefore, choice A is correct as an increase in A always produces an increase in X.